Lithium and lithium-ion batteries are used to power a number of medical devices and medical electrical equipment: hearing aids, pacemakers, surgical tools, medical defibrillators, robots, infusion pumps, monitors, and meters are just some examples of medical devices that have benefited from implementing lithium batteries into their design and function.
Because of their high energy density, lithium batteries are susceptible to overheating and can become a fire hazard, so they have been classified as a dangerous good. In order to be transported, they must meet certain provisions laid out in the global UN 38.3 standard. The standard applies to all areas in the lithium battery transportation chain: sub-suppliers to end-product manufacturer; manufacturer to distributor; in or out of the product; in the field; during product return; or within non-original packaging. It is important for the medical industry to be familiar with these requirements as the use of these batteries becomes more prevalent.
UN 38.3 applies to batteries either transported on their own or within a device. A universal standard, it has been adopted by regulators and competent authorities around the world, making it a requirement for access to multiple, even global, markets. The UN 38.3 protocol is a key component of the dangerous regulations and includes identifying/classifying lithium batteries, testing/qualification requirements, design guidance/conditions, and packaging/shipping obligations.
There are four classifications for these batteries, based on whether they are lithium or lithium-ion and how they are shipped. The requirements for classification vary based on the manner shipped, versus battery type, and can be summed up in the following way:
- UN 3090 for lithium batteries and UN 3480 for lithium-ion batteries apply to: cells shipped alone, batteries shipped alone, consignment of cells and batteries, modules or other incomplete battery sub-assemblies, power banks, powerpacks, and batteries shipped in a separate package from the device they power (even if the device and batteries are on the same consignment or shipment).
- UN 3091 for lithium batteries within a device and UN 3481 for lithium-ion batteries within a device apply to devices with their batteries installed; devices packed with their battery in the same package, though the battery is not installed in the product; up to two spare batteries shipped in the same package as the device (i.e. one installed, two spares or none installed, two spares).
Testing and Qualification
UN 38.3 requires several tests to ensure the relative safety of the batteries during transport. They vary based on the battery and components, as well as what they assess, and include:
- Tests T1-T5, conducted on the same samples, in order, on all battery types [altitude simulation (Test T1), thermal testing (Test T2), vibration (Test T3), shock (Test T4), and external short circuit (Test T5)]
- Test T6, conducted on the primary and secondary cells, evaluates impact and crush
- Test T7 is intended for secondary batteries, assessing effects of an overcharge
- Test T8 is also conducted on the primary and secondary cells, assessing forced discharge
The most recent update to the standard, 6th Edition, Amendment 1, went into effect at the start of 2019, and it includes several key changes regarding battery testing:
- Integrated batteries: Updated to allow testing of batteries within equipment.
- Disassembly: Allows for additional test criteria; we recommend any cases that may be considered “borderline” disassembly to be treated as test failures.
- Rechargeable batteries considerations: Changes to the cycling requirements reducing to 25 charge/discharge cycles prior to test, from 50 previously; also updates testing tables to reflect these changes.
- Test summary: Now clearly defines “battery test summary,” as well as the requirement that the test summary “shall be made available.” Additionally, it notes the requirement for the name and title of the signatory as an indication of validity.
With these requirements, it is important to remember to get or create a test report summary based on successful completion of UN 38.3 testing. These test report summaries must be available from the shipper upon request. They do not need to be included in shipments; however, it may be wise to include when further transportation will occur. Get test reports from cell vendors and subcontractors to complete the test summary for your shipments, maintaining the supporting information.
It is also important to consider what level or subassembly of battery will be offered for shipment. Identify the samples tested and the models/versions to be covered by a single test report. Be aware of model number changes, which may call the test summary into question.
Design Guidance and Conditions
Several clauses of the regulations relate to design guidance, which includes adherence to the testing and qualification requirements, as well as the incorporation of a safety venting device or design elements to preclude a violent rupture; an effective means of preventing external short circuits; parallel connected cells/cell-strings equipped with a means to prevent dangerous reverse current flow; and the requirement for manufacturing to be done under a quality management system.
Packaging and Shipping
The most recent updates to the regulation include new labels to better, yet more simply, illustrate the risk of fire associated with the batteries in the package (individually or within a device), as well as a separate lithium battery version of the Class 9 placard. Passenger aircraft restrictions have also been updated to prohibit transport of lithium-ion cells/batteries (along with already-prohibited lithium-metal cells/batteries) as cargo on passenger planes (this does not apply to batteries in devices), requiring these items to be labeled for cargo aircraft only. Lithium-ion batteries shipped alone must be set at or below 30 percent state of charge (SOC) for cargo air shipment. To ensure you meet this requirement, document the method used, and how the shipment was verified. For medical device batteries that must be shipped at >30 percent SOC due to medical necessity (i.e. they must have full capacity upon receipt) after shipment, a competent authority approval may be sought, which will allow for air shipment of such batteries at higher charge levels. Note that medical device batteries are not automatically exempted from this requirement.
As medical device manufacturers seek to make products smaller, more portable, and longer lasting, lithium and lithium-ion batteries are a valuable resource for power. However, manufacturers must remember that the power of these batteries comes with additional needs when it comes to safely transporting the power source and the device containing said source. Knowing the basics and beyond of UN 38.3 can play an important role in meeting these requirements in multiple markets across the globe.
Rick Byczek is the global director of transportation technologies at Intertek, a London, U.K.-based total quality assurance provider to industries worldwide.